Fix missing headerview gap when not showing frame in TableView
Fix missing headerview gap when not showing frame in TableView

Tested on all three platforms and looks better.

Change-Id: I8a68dfc7fe97a05c4313ac10de2f93dabec5a964
Reviewed-by: Gabriel de Dietrich <57b5c683f0b6abfc17ef151d5b68c8944258b63a@digia.com>

kobolabs/qtquickcontrols,drgvond/qtquickcontrols,kobolabs/qtquickcontrols,mizukusak/qtquickcontrols,drgvond/qtquickcontrols,mizukusak/qtquickcontrols,kobolabs/qtquickcontrols,mizukusak/qtquickcontrols,drgvond/qtquickcontrols